TY - JOUR
T1 - Disentangling Losses in Tantalum Superconducting Circuits
AU - Crowley, Kevin D.
AU - Mclellan, Russell A.
AU - Dutta, Aveek
AU - Shumiya, Nana
AU - Place, Alexander P.M.
AU - Le, Xuan Hoang
AU - Gang, Youqi
AU - Madhavan, Trisha
AU - Bland, Matthew P.
AU - Chang, Ray
AU - Khedkar, Nishaad
AU - Feng, Yiming Cady
AU - Umbarkar, Esha A.
AU - Gui, Xin
AU - Rodgers, Lila V.H.
AU - Jia, Yichen
AU - Feldman, Mayer M.
AU - Lyon, Stephen A.
AU - Liu, Mingzhao
AU - Cava, Robert J.
AU - Houck, Andrew A.
AU - De Leon, Nathalie P.
N1 - Publisher Copyright:
© 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
PY - 2023/10
Y1 - 2023/10
N2 - Superconducting qubits are a leading system for realizing large-scale quantum processors, but overall gate fidelities suffer from coherence times limited by microwave dielectric loss. Recently discovered tantalum-based qubits exhibit record lifetimes exceeding 0.3 ms. Here, we perform systematic, detailed measurements of superconducting tantalum resonators in order to disentangle sources of loss that limit state-of-the-art tantalum devices. By studying the dependence of loss on temperature, microwave photon number, and device geometry, we quantify materials-related losses and observe that the losses are dominated by several types of saturable two-level systems (TLSs), with evidence that both surface and bulk related TLSs contribute to loss. Moreover, we show that surface TLSs can be altered with chemical processing. With four different surface conditions, we quantitatively extract the linear absorption associated with different surface TLS sources. Finally, we quantify the impact of the chemical processing at single-photon powers, the relevant conditions for qubit device performance. In this regime, we measure resonators with internal quality factors ranging from 5 to 15×106, comparable to the best qubits reported. In these devices, the surface and bulk TLS contributions to loss are comparable, showing that systematic improvements in materials on both fronts are necessary to improve qubit coherence further.
AB - Superconducting qubits are a leading system for realizing large-scale quantum processors, but overall gate fidelities suffer from coherence times limited by microwave dielectric loss. Recently discovered tantalum-based qubits exhibit record lifetimes exceeding 0.3 ms. Here, we perform systematic, detailed measurements of superconducting tantalum resonators in order to disentangle sources of loss that limit state-of-the-art tantalum devices. By studying the dependence of loss on temperature, microwave photon number, and device geometry, we quantify materials-related losses and observe that the losses are dominated by several types of saturable two-level systems (TLSs), with evidence that both surface and bulk related TLSs contribute to loss. Moreover, we show that surface TLSs can be altered with chemical processing. With four different surface conditions, we quantitatively extract the linear absorption associated with different surface TLS sources. Finally, we quantify the impact of the chemical processing at single-photon powers, the relevant conditions for qubit device performance. In this regime, we measure resonators with internal quality factors ranging from 5 to 15×106, comparable to the best qubits reported. In these devices, the surface and bulk TLS contributions to loss are comparable, showing that systematic improvements in materials on both fronts are necessary to improve qubit coherence further.
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U2 - 10.1103/PhysRevX.13.041005
DO - 10.1103/PhysRevX.13.041005
M3 - Article
AN - SCOPUS:85174854728
SN - 2160-3308
VL - 13
JO - Physical Review X
JF - Physical Review X
IS - 4
M1 - 041005
ER -